A variety of wired and wireless communications devices, each offering a panoply of capabilities, are available to suit an individual's needs. Wired communications devices are those which require a signal-conducting path, other than air, between the communications device and a communications system, such as a central office switch or private branch exchange (PBX). The signal-conducting path can take many physical forms, including a number of different kinds of metallic conductors or optical fibers. In contrast, wireless communications devices, such as paging and cellular radio communications devices, utilize the air as the medium to transport signals to and from the communications system. The distinction between paging and cellular radio devices resides in their communications capabilities. Paging devices are portable one-way communications devices which respond to associated radio signals which are broadcasted while cellular radio devices provide full two-way communications capabilities.
With a paging device, the reception of a predetermined radio signal typically activates an audible and/or visual alarm to indicate that the person carrying the pager should make a call to a predetermined telephone number to receive a message. Or, in the alternative, the paging device may have the capability to receive an incoming message which can be displayed. This message communicates a predefined amount of information which may be the telephone number of a calling party.
There are many situations where an individual may have a pager as well as a wired or wireless communications device possessing full two-way communications capabilities to receive incoming calls. Such situations include a hospital, manufacturing, education and general office environments where it is desirable that an individual be notified of incoming calls independent of whether that individual is in close proximity to his/her associated full, two-way communications device. In such situations, it is necessary that a communications system have the capability of notifying a called party of an incoming call by signalling any paging device associated with that called party. Present techniques which provide such signalling broadcast a signal to the paging device associated with the called party. The shortcoming of this technique is that a telephone number different from that associated with the called party must be dialed in order to activate such a broadcast. As a result, a calling party must dial two different telephone numbers, the first associated with the called party's wired full two-way or wireless communications device and then, if the called party does not answer, dials a second number to alert the called party via his/her paging device. If the second number is dialed, the calling party must also wait for a return call from the called party since the paging device cannot provide two-way communications capabilities. This scenario often results in considerable telephone tag, i.e., situations where two individuals periodically try to contact one another and fail because the other person is unavailable.
While the use of cellular communications devices with full two-way communications devices can alleviate much of the foregoing problems associated with paging devices, cellular radio devices give rise to a set of other problems. One such problem is that cellular telephones are expensive and this expense is not merely that of the portable communications device but also that of the necessary transceivers which must be disposed to provide substantially uniform communications coverage within a given environment. It should be noted in this regard that the requirements of supporting apparatus associated with two-way cellular radio devices are considerably more sophisticated than those associated with paging devices because the former must provide intelligible two-way communications. Another problem is that the requirements for cellular two-way radio devices may be difficult, if not impossible, to achieve in certain noisy environments. Still another problem is that the required radio spectrum to provide cellular radio communications may not be available in certain environments or geographical areas.
In light of the foregoing, there are still considerable applications for paging devices and it would be desirable if a scheme could be devised which would eliminate the problems associated with the use of such devices.